Not really the case .. and the AFM leads one by the hand in any case.
Easy for you to say, jt...
Having detailed and accurate obstacle data is the problem .. which is why pilot calculations generally are based on simplified data appropriate to obstacle clear surface data.
Oh, I'd agree that most pilots could find the WAT limits if there were no obstacles in the regulatory departure corridor.
I'm only suggesting that if one gave a reasonably complex departure problem with both close-in and distant obstacles -- one that would introduce thrust time limits and selections of clean-up heights -- to 100 line pilots, it would be surprising if not impossible to find more than five correct answers to the question of "what is the maximum allowable TOW?"